Type or namespace SigninManager<> could not be found Identity 3.1.1 Mediatr 8.0.0 - asp.net-core

Question

I am trying to implement Identity using the Mediatr library and pattern...
The code i am using did work in dotnetcore 2.x and identity 2.2 but is broken in dotnetcore 3.x and identity 3.1.1...
My Application class library is netstandard2.1 and hase the following dependencies set.
<PackageReference Include="FluentValidation.AspNetCore" Version="8.6.1" />
<PackageReference Include="MediatR.Extensions.Microsoft.DependencyInjection" Version="8.0.0" />
<PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="3.1.1" />
I have my request handler like so;
public class Handler : IRequestHandler<Query, AppUser>
{
private readonly UserManager<AppUser> _userManager;
private readonly SignInManager<AppUser> _signInManager;
public Handler(UserManager<AppUser> userManager, SignInManager<AppUser> signInManager)
{
_userManager = userManager;
_signInManager = signInManager;
}
public async Task<AppUser> Handle(Query request, CancellationToken cancellationToken)
{
var user = await _userManager.FindByEmailAsync(request.Email);
if (user == null)
{
throw new Exception("Unauthorized");
}
// var result = await _signInManager.CheckPasswordSignInAsync(user, request.Password, false);
var result = await _userManager.CheckPasswordAsync(user, request.Password);
if (result)
{
return user;
}
throw new Exception("Unauthorized");
}
}
The issue I am having here is that I cannot resolve SignInManager anymore and I am not sure why. I cannot find much info about any of the breaking changes around this between identity versions either.
Where has the SignInManager gone? I thought UserManager were in the same namespace and UserManager resolves just fine. Super confused right now, as you can see, i am about ready to cheat my way out but it doesn't sit right with me.
With the same dependencies in my API project I can reference SignInManager with the same namespace and i can use it to sign in directly in the controller. How can i decouple this in to a Mediatr Handler?

Answer 1

Starting with version 3.0, ASP.NET Core is no longer fully distributed through NuGet. Instead, it is shipped as part of the .NET Core runtime as a shared framework. Only optional packages, like the Microsoft.AspNetCore.Identity.EntityFrameworkCore are still distributed through NuGet. However, those packages do not have transient dependencies defined which will automatically work, so you will still need to properly reference this shared framework in order to use these types.
In order to do this, you will need to switch your project to target netcoreapp3.1 since ASP.NET Core only runs on .NET Core and won’t work with .NET Standard.
Once you have done that, you can reference the shared framework using a framework reference. So your project file should look like this:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>netcoreapp3.1</TargetFramework>
</PropertyGroup>
<ItemGroup>
<FrameworkReference Include="Microsoft.AspNetCore.App" />
</ItemGroup>
<ItemGroup>
<PackageReference Include="FluentValidation.AspNetCore" Version="8.6.1" />
<PackageReference Include="MediatR.Extensions.Microsoft.DependencyInjection" Version="8.0.0" />
<PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="3.1.1" />
</ItemGroup>
</Project>